Surfacing apparatus



Oct. 13, 1942. H. R. STRATFORD 2,298,318

' SURFACING APPARATUS Filed March 20, 1940 INVENTOR.

fiererf P. Sfrafforcf ATTORNEYS.

Patented Oct. 13, 1942 UNITED STATES PATENT OFFICE SURFACDI G APPARATUS Herbert R. Stratford, Cleveland, Ohio, assignor to The Stratmore Company, Wilmington, Del., a corporation of Delaware Application March 20, 1940, Serial No. 324,988

5 Claims.

This invention relates, as indicated, to surfacing apparatus, but has reference more particularly to new and useful improvements in abrasive elements for use in surfacing or abrading wood and metal panels coated with various materials, and the like.

In United States Letters Patent No. 2,082,916, granted to me June 8, 1937, there is disclosed an element for heavy abrading work in the form of a disc of thin flexible metal, preferably of steel, adjacent the periphery of which is attached as by means of adhesive, a layer of abrasive material.

Steel discs of the aforesaid character are usually so thin that they are subject to breakage or tearing, which may result from shock occasioned by the disc striking against hard or jagged welds and other irregularities in the work surface, or by striking against other objects in the plant or workshop. When this occurs, the person of the operator and others about him may be endangered by the loosened or flying particles of metal.

In addition to this hazard, there is another hazard involved in the danger to the operator of being accidently cut or scratched by the sharp edge of the steel disc in the mere handling of the surfacing apparatus, and against which the operator, in the ordinary course of work, cannot effectively guard or protect himself. In other words, the rapidly rotating disc acts like a revolving knife, and extremely bad cuts are likely to result from mere contact of the hands of the operator with the sharp peripheral edge thereof.

Moreover, these discs are usually stamped from steel strip or sheet steel, and thus are left with K a relatively sharp corner at the junction of the outer surface of the disc and the peripheral edge thereof. When such a disc is rotated at a high rate of speed and applied at an angle to the work in the manner customary when rotating discs are used, and the operator exerts a manual pressure at the center of the discs on the driving shaft, the sharp corner of the disc to which reference has been made is likely to scratch or otherwise mar smooth portions of the Work which are not intended to be in any way affected by the abrading action of the disc. This scratching or marring of the work may occur at any time during the interval between the application of the disc to the work and the flexing of the peripheral portion thereof to the point where the latter lies parallel with the work surface, as shown in Fig. 6 of my aforesaid patent. Such scratching or marring of the work entails additional labor and abrasives in repairing the damage which has been 5 Cit done, and in some cases, the injury may be so great as to be irreparable.

The invention, accordingly, has as among its major objects the provision of means which will prevent or minimize the aforesaid danger resulting from breakage or tearing of the disc, the protection of the operator from being cut or otherwise injured, either in picking up the apparatus or by the rapidly revolving knife-like edge of the steel disc thereof, and the provision of means for either eliminating or minimizing the aforesaid tendency of the steel disc when in use to scratch or otherwise mar portions of the work which are not intended to be affected by the abrading action of the disc.

To the accomplishment of the foregoing and related ends, said invention, then, consists of the means hereinafter fully described and particularly pointed out in the claims; the annexed drawing and the followingdescription setting forth in detail certain'structures embodying the invention, such disclosed means constituting, however, but a few of the various mechanical forms in which the principle of the invention may be used.

In said annexed drawing:

Fig. 1 is a cross-sectional view of the peripheral portion of a disc embodying the features of the invention; Fig. 2 is a vertical section through a disc similar to that shown in Fig. 1, but provided with a supporting and protecting pad; Fig. 3 is a vertical section through a disc similar to that shown in Fig. 1, but provided with a backing of a somewhat different type than that shown in Fig. 2; Figs. 4, 5 and 6 are views similar to Fig. 1, but showing various modifications of the invention.

Referring more particularly to Fig. 1, there is shown a disc ll] of thin flexible metal, preferably of steel, although other metals can also be used. This metal disc is secured to a driving shaft of conventional form and design, by means of a fastening stud passing through a central aperture of the disc. The operator grasps the apparatus by means of suitable handles (not shown) associated with the driving shaft and applies pressure axially of the shaft. The ring of abrasive 4 on the peripheral portion of the outer surface 5 of the disc is placed in contact with a Weld seam or the like and by virtue of the application of the aforesaid axial pressure, the marginal portion of the disc is deflected out of its normal plane. In applying the disc at an angle to the work, the sharp corner at the junction of the outer surface 5 of the disc and the peripheral edge thereof is likely to scratch or otherwise mar smooth portions of the work which are not intended to be in any way affected by the abrading action of the disc.

In order to avoid the possibility of scratching the work when the disc is initially applied to the work, I preferably provide the disc I (Fig. 1) with a smoothly rounded upturned flange II at the outer margin or periphery thereof. In the useof such a disc, the work will be engaged by the smoothly rounded flange when the disc is first applied to the work, and injury to the work surfaces thereby avoided. The turning up of such a flange on the disc decreases the flexibility of the disc to a certain extent, but this may be compensated by the use of metal of lighter gauge than would otherwise be employed in making the disc.

If desired, the disc, as shown in .Fig. 1 may be provided with a backing pad 12 of felt, sponge rubber or other material, as shown in Fig. .2, which is flexible and/or compressible in order that the metal disc may be free to flex, or a series of stepped plates l3, -l4 and I5, as shown in Fig. 3 may be employed as a backing. Where a ;pad is employed, it should preferably extend slightly beyond the periphery of the disc, as shown, for a purpose to be presently described.

In that form of the invention illustrated in F g. 4, the disc is left unflanged, but the abrasive 16, instead of being secured directly to the steel disc, is adhesively secured to a sheet I! of cloth or fabric, such as canvas, which in turn is adhesively secured to the disc. By extending the canvas over the peripheral edge 8 of the disc, the sharp corner of the disc is covered by a relatively soft material, thereby avoiding direct contact of this corner with the work surface.

In that form of the invention illustrated in Fig. 6, the steel disc 2| is left unflanged, but a certain degree of protection against marring of a surface by a sharp corner 22 is afforded by adhesively securing to the outer surface of the disc a sheet of cloth or fabric 23, which extends to the peripheral edge of the disc and bears on its outer surface the abrasive 24.

In those forms of the invention shown in Figs. 4, 5 and 6 the sheets of cloth or fabric, in addition to their function of providing protection against marring of the work surface, will act to hold any portions of the disc which might break off during use of the disc from flying off the disc and injuring the operator or others about him. In other words, the canvas or other fabric, being adhesively secured to the disc, will prevent or minimize the dangers resulting from breakage of the disc. For this purpose, any material which is adhesively or otherwise secured to the disc and which forms a backing or holder for the abrasive may be used instead of cloth or fabric. A layer of rubber which is vulcanized or otherwise bonded to the steel disc may be mentioned as an example of such material.

ill

By having the edge of the pad I2 extend beyond the periphery of the disc Ill, as shown in Fig. 2, and at the same time turning up the edge of the disc, considerable protection is afforded the operator against the danger of being cut or otherwise injured by the edge of the steel disc. Similar protection is afforded the operator in the use of the discs illustrated in Figs. 3, 4, 5 and 6.

Other modes of applying the principle of my invention may be employed instead of the one explained, change being made as regards the structure herein disclosed, provided the means stated by any of the following claims or the equivalent of such stated means be employed.

Itherefore particularly point out and distinctly claim as my invention:

1. Surfacing apparatus comprising a disc of thin flexible metal having abrasive material secured thereto, said disc having a smoothly rounded upturned flange at the periphery thereof, and a protective backing for said disc.

2. Surfacing apparatus comprising a thin, flexible abrasive disk of metal, said disk having a smoothly rounded upturned edge at the periphery thereof.

3. A flat radial face abrasive disk adapted to be moved bodily relative to the work comprising a sheet of thin, flexible metal adapted to flex under pressure when said disk is applied to the work at an angle, and means on said disk including an upturned, smoothly rounded flange at its periphery'to prevent the edge at the junction of said radial face and the periphery of said diskfrom scratching the work surface when said disk is applied at said angle.

4. A flat radial face abrasive disk adapted to be moved bodily relative to the work comprising a sheet of thin, flexible metal adapted to flex under pressure when said disk is applied to the work at an angle, means on said disk including an upturned, smoothly rounded flange at its periphery to prevent the edge at the junction .of said radial face and the periphery of said disk from scratching the work surface when said disk is applied at said angle, and a protective backing for said disk.

5. A flat radial face abrasive disk adapted 'to be moved bodily relative to the work comprising a sheet of thin, flexible metal adapted to flex under pressure when said disk is applied to the work at an angle, means on said disk including an upturned, smoothly rounded flange at its periphery to prevent the edge at the junction of said radial face and the periphery of said disk from scratching the work surface when said disk is applied at said angle, and a protective backing for said disk, said backing extending beyond the peripheral edge of said disk.

HERBERT R. STRATFORD. 

